Reassessing Service Split-Join Criteria

Vasco Figueira:

TL;DR “Microservices” was a good idea taken too far and applied too bluntly. The fix isn’t just to dial back the granularity knob but instead to 1) focus on the split-join criteria as opposed to size; and 2) differentiate between the project model and the deployment model when applying them.

There are build patterns that give us total control over the relative visibility between components and over how they compose into deployables. One build to many deployables, many to one or anything in between is possible. Shifting concerns left helps us build better software. An earlier error is a better error. Constraints liberate.

The tensions and constraints that shape the arrangement of our projects, modules and dependencies are of a different nature than those shaping the arrangement of our deployables. A little build-fu goes a long way in combining development friendliness with mechanical sympathy.